(A) Field of the Disclosure
The present disclosure relates to a probing apparatus with on-probe device-mapping function, and more particularly, to a probing apparatus with on-probe device-mapping function implemented by moving the probe out of focus of the optical inspection module while keeping the device under test in the field of view of the optical inspection module.
(B) Description of the Related Art
Optical imaging systems are used for inspection of semiconductor devices such as light-emitting diodes (LED) and integrated circuit devices. In a typical semiconductor device test process, the wafer is first placed on blue tape before being cut into individual semiconductor devices where each semiconductor device is isolated from others on the wafer. The blue tape with the semiconductor devices on it is then mounted onto a circular rim for testing. The imaging system provides the means for navigating the semiconductor devices on the rim as well as the probing process. As the semiconductor device positions are slightly distorted during the cutting from wafer and transfer to the rim, and in view of the large number of semiconductor devices to be inspected and probed on the wafer, device mapping is usually performed prior to probing. The mapping collects and records the information of each of the semiconductor devices including its position, presence or absence, ink marking, etc. In a typical device test cycle, a group of semiconductor devices is positioned under the field of view (FOV) of the imaging system. A semiconductor device pattern is then learned by the imaging system and will be used as master pattern for the search of other semiconductor devices within the FOV using the commonly used pattern-matching technique.
However, because the presence of the probes above the semiconductor devices can cause blocking of the image and incomplete mapping of the semiconductor devices, most inspection apparatuses use a second imaging system when performing the device mapping. The second imaging system is mounted some distance away from the first imaging system and the semiconductor device positioning stage needs to move the semiconductor devices to the second imaging system for the device-mapping process. After the device mapping is completed, the semiconductor devices are moved back to the first imaging system for probing. The imaging system's optical centers for probing and mapping need to be precisely aligned in order to avoid incorrect positioning of the semiconductor devices.
The inspection apparatus described above, however, has the disadvantage of requiring two imaging systems, as well as the disadvantage of requiring precise position alignment of the two optical centers. Further disadvantages include the time requirement for the semiconductor device positioning stage to move from one imaging system to the other and the extra travel range required to move the semiconductor device positioning stage between the two imaging systems.
U.S. patent publication number US 2009/0236506 A1 discloses an On-wafer test system and method for light-emitting devices, such as light-emitting diodes (LEDs). The system comprises a wafer including an LED die designed to emit light and a light-collection component configured to collect substantially all of the emitted light and to scatter the emitted light to produce a distribution of scattered light. The system further comprises a detector associated with the light-collection component and designed to detect a portion of the scattered light.